NAME

cron − clock daemon

SYNOPSIS

/etc/cron

DESCRIPTION

The cron command executes commands at specified dates and times.  Regularly scheduled commands can be specified according to instructions found in crontab files in the directory /usr/spool/cron/crontabs.  Users can submit their own crontab file via the crontab(1) command. Commands which are to be executed only once may be submitted via the at(1) command.

The cron command only examines crontab files and at command files during process initialization and when a file changes via crontab or at. This reduces the overhead of checking for new or changed files at regularly scheduled intervals.

Since cron never exits, it should be executed only once.  This is done routinely through /etc/rc2.d/S75cron at system boot time.  /usr/lib/cron/FIFO is used as a lock file to prevent the execution of more than one cron.

FILES

/usr/lib/cron main cron directory

/usr/lib/cron/FIFO used as a lock file

/usr/lib/cron/log accounting information

/usr/spool/cron spool area

/usr/default/cron

SEE ALSO

at(1), crontab(1), sh(1). 

DIAGNOSTICS

To keep a log of all actions taken by cron , set CRONLOG=YES in the file /etc/default/cron.  No logging is done if you set CRONLOG=NO (default setting).  Keeping a log is a user-configurable option.  cron usually creates very large log files. 

\*U  —  Version 1.0